When a writing or recorded statement or part thereof is introduced by a party, an adverse party may require that party at that time to introduce any other part or any other writing or recorded statement which ought in fairness to be considered contemporaneously with it.

If only part of an alleged admission or confession is introduced against the accused, the defense, by cross-examination or otherwise, may introduce the remaining portions of the statement.

The recent opinion of the U.S. Navy-Marine Corps Court of Criminal Appeals in United States v. Foisy, 2010 WL 2824964 (N.M.Ct.Crim.App. 2010), does a good job of laying out how military courts apply this latter Rule.

In Foisy, a panel of members with enlisted representation sitting as a general court-martial convicted Robert Foisy, contrary to his pleas, of violating a lawful general order and aggravated sexual assault based upon acts that he allegedly committed against LCpl S. Foisy gave an initial statement regarding the alleged crime on November 30, 2008, in which he

provided a detailed explanation of the evening in question, as well as events of the previous few days that bore on the matter in controversy....[T]he appellant noted that LCpl S had been "giving me strong sexual signs like saying I can't wait to have sex again because her boyfriend is gone right now [, and] she would touch my stomach and when she hugged me she would grind her self into me...." He also stated that when he left the room, LCpl S was wearing sweat pants and a hooded sweatshirt, but when he reentered the room, she climbed into bed with LCpl Rumsey wearing only a tee shirt and underwear, getting into the rack with LCpl Rumsey. Shortly thereafter, the appellant awoke with LCpl S at the sink washing her mouth out with water and making statements about being hot. He further said that LCpl S began to take her underwear off, but that he told her not to. According to the appellant's statement, a short time later LCpl S again got out of the rack and went to the sink, made additional statements about being hot and then took off her underwear. According to the appellant, LCpl S then stepped over him, got back into the rack, naked from the waist down, with her buttocks hanging over the bed, "kind of stuck up in the air like she was waiting for some one [sic] to do something...." The appellant stated that he covered LCpl S, but that she uncovered herself again. It was at that point that the appellant sa[id] he made physical contact with LCpl S.

On January 26, 2009, Foisy gave a second statement which began

when the appellant was nude, looking at and touching a naked LCpl S. [The second statement] omit[ted] all of the details which put the touching in context....

The agent typing up Foisy's second statement noted that it was a "supplementary statement." At the court-martial, the Government introduced Foisy's second statement, and, when Foisy sought to introduce his initial statement, the Government objected, citing hearsay, lack of foundation, and the rape shield rule. The military judge agreed and rejected Foisy's argument that the initial statement was admissible under the rule of completeness.

In addressing Foisy's ensuing appeal, the U.S. Navy-Marine Corps Court of Criminal Appeals noted that both Military Rule of Evidence 106 and Military Rule of Evidence 304(h)(2) applied and that the opinion of the United States Court of Appeals for the Armed Forces in United States v. Rodriguez, 56 M.J. 336 (U.S. Armed Forces 2002), set forth a non-exhaustive list of factors to consider in cases governed by these Rules:

(1) Has the prosecution attempted to "pick out the incriminating words in the statement or discussion and put them in evidence while at the same time excluding the remainder of the statement or conversation, in which the appellant sought to explain the incriminating passages"? (2) Is the appellant's subsequent statement separate and unrelated from the subject matter of the original confession, or is it part of or the product of the same transaction or course of action? (3) What is the elapsed time between the two statements, and were they made at different places and to a different set of persons? (4) Was the second statement made at the specific request of the appellant or the Government? (5) Was the defense invoking the rule of completeness as a matter of fairness, or merely attempting to present evidence of a defense without subjecting the appellant to cross-examination? (6) Did the appellant engage in a "pattern of deception with a variety of persons, and then argue that belated candor in a different setting justifies the introduction of otherwise inadmissible hearsay"?

According to the court,

The only factors clearly weighing in favor of exclusion of the initial statement are that the statements were taken about two months apart, and that the statements were taken by different agents. A closer balance exists with regard to the fifth factor. Undeniably, the appellant would have been able to present evidence of his defense without subjecting himself to cross-examination, and the complete statement would have provided a far more exhaustive explanation of events than contemplated by the Government when the partial statement was offered and admitted. However, on balance, this factor weighs in favor of admission of the statement as well, for the Government made the election to offer part of the statement in the first instance, prompting the defense to seek fairness through completion. The rules of completeness exist to address precisely what unfolded at trial in this case.

Although the court did not detail exactly how Foisy fared under each of the other factors, it found that

The appellant made two statements, in the same place, to agents of the same criminal investigative agency, explaining the same events, to defend against the same accusation....The two statements are manifestly related. In fact, inclusion of the qualifying language, "[t]his is a supplementary statement to add to the previous statement I gave to NCIS investigators," reflects the dependent nature of the admitted statement to the excluded statement. Standing alone, [the second statement] contains a statement, incriminating when taken out-of-context, which was "picked out" and presented to the members, while every effort was made to prevent the members from seeing the rest of the statement explaining that out-of-context statement. We reject any argument that the appellant himself was the architect of the second, admitted statement, and thus, should bear the impact of his own admissions as they stand, precisely because the agent's interrogation methodology blunted any need to again provide the details of the first statement: the appellant did not include the background details because the agent's own drop-in line explicitly incorporated the first statement into the "supplementary" statement. It is "manifestly unfair" to require the appellant to face his inculpatory admissions while simultaneously barring him from introducing the very statement his inculpatory remarks specifically supplemented by reference, especially when, as in this case, the appellant's story did not change.

The court thus found that the military judge erred in excluding Foisy's first statement, and because it found that Foist was materially prejudiced, it set aside Foisy's conviction.